Physicist Enrico Fermi packed up and emigrated to the United States in 1938, the same year he was awarded the Nobel Prize for physics. Instead of returning home after accepting the award in Stockholm he continued on to the United States because the atmosphere in Italy was beginning to become toxic for his Jewish wife as German Nazis gained power in the region. Soon afer his arrival in the United States he found himself at the University of Chicago where he continued his work on nuclear reactions as part of the Manhattan Project (the group of scientists charged with creating the worlds first nuclear bomb).
When construction of an off-campus site was postponed Fermi suggested the reactor be built in a squash court underneath the stands of the University’s athletic field. The reactor was assembled in November 1942 and on December 2 the world’s first man-made, self-sustaining nuclear reaction was initiated in the reactor named Chicago Pile-1.
The development of this technology led to the first nuclear bomb test only a few years later, in July 1945, and later still the two atomic bombs dropped on Hiroshima and Nagasaki.
Extra fun fact: the element fermium is named after him
